By Neuroskeptic
I am sitting reading a book. After a while, I get up and make a cup of coffee.
I’ve been thinking about this scenario lately as I’ve pondered ‘what remains to be discovered’ in our understanding the brain.
By this I mean, what (if anything) prevents neuroscience from at least sketching out an explanation for all of human behaviour?
A complete explanation of any given behaviour – such as my reading a particular book – would be impossible, as it would require detailed knowledge of all my brain activity.
But neuroscience could sketch an account of some stages of the reading. We have models for how my motor cortex and cerebellum might coordinate my fingers to turn the pages of my book. Other models try to make sense of the recognition of the letters by my visual cortex.
This is what I mean by ‘beginning to account for’. We have theories that are not wholly speculative. While we don’t yet have the whole story of motor control or visual perception, we have made a start.
Yet I’m not sure that we can even begin to explain: why did I stop what I was doing, get up, and make coffee at that particular time?
The puzzle, it seems, does not lie in my actual choice to make some coffee (as opposed to not making it.) We could sketch an explanation for how, once the mental image (memory) of coffee ‘crossed my mind’, that image set off dopamine firing (i.e. I like coffee), and this dopamine, acting on corticostriatal circuits, selected the action of making coffee over the less promising alternatives.
But why did that mental image of coffee cross my mind in the first place? And why did it do so just then, not thirty seconds before or afterwards?